The mind, becoming accustomed to certain habits of thought and response, does not find it easy to adjust itself to these new claims of its own perceptions, owing to the inertia caused by impressions of previous modes of thought and conduct. This process of readjustment in the light of true values takes the form of what we call controlling the mind.
This control is not a mechanical or forcible twisting of the mind. It is an effort of the mind to overcome its own inertia.
It is fundamentally creative and not negative in its purpose, for it is an attempt of the mind to arrive at self-adjustment in order to release the expression of the true values of life.
Creative control becomes possible because the source of light is within everyone; and though Self-illumination is prevented by the veil of sanskaras, it is not all darkness even within the boundaries of ordinary human consciousness. The ray of light consists of a sense for true values and guides man onward with varying degrees of clarity according to the thickness of the veil of sanskaras.
The process of the negation of sanskaras is at the same time the process of understanding true values.
-Discourses 7th Ed., p50